π Node [[ospf]]
β³ π Resource @bbchase/ospf
- Open Shortest Path First
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References
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[[Routing Protocol]]
- #[[Link-state [[Routing Protocol]]]]
- [[IGP]]
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History
- standardized in 1989
- Developed largely by DEC
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Terms
- LSDB (Link State Database): A database that stores LSAs. This is how OSPF builds a picture of the network. A network topology map.
- LSA (Link State Advertisement): A data structure that describes part of the network.
- DBD or DDP (Database Description packet): A list of LSAs that a router has. This packet does not contain LSAs, just the headers. This is sent to a neighbor so it can figure out which LSAs to request.
- LSU (Link State Update): A packet containing LSAs.
- LSAck (Link State Acknowledgement): Confirms receipt of an LSU.
- LSR (Link State Request): A packet which requests a list of LSAs that the router has found are missing or out of date based on its neighbor’s Dababase Description (DBD).
- Neighbors: A relationship between routers on the same data link that, once established, allows them to exchange their LSDBs.
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OSPF Areas
- 32-bit number, can be decimal or dotted-decimal
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Area 0 (0.0.0.0)
- Backbone area
- All areas must connect to Area 0
- Stub Area
- Not-so-stubby Area (NSSA)
- Totally Stubby Area
- Totally Stubby NSSA
- Transit Area
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OSPF Router Types
- IR (Internal Router)
- BR (Backbone Router)
- ABR (Area Border Router)
- ASBR (Autonomous System Border Router)
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OSPF Router Attributes
- DR (Designated Router)
- BDR (Backup Designated Router)
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LSA Types
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Related
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